Murine adult hematopoietic cells produce adult erythrocytes in fetal recipients

Bone marrow cells from normal adult mice were introduced by microinjection via the placenta into W/W^v genetically anemic fetuses of 11 days' gestation. After birth, erythrocytes were fractionated by fluorescence-activated cell sorting on the basis of antibody binding to a fetal-specific antigen (Ft). Lysates of Ft-positive, i.e., fetal, erythrocytes did not detectably contain hemoglobin of the donor type, as judged from electrophoresis of strain-specific hemoglobin variants. Thus, adult hematopoietic bone marrow cells did not resume fetal differentiation despite their post-transplant maturation in a fetal environment.     

Plasticity of epidermal adult stem cells derived from adult goat ear skin

Here we report the isolation and characterization of pluripotent stem cells from adult goat skin. We found that these primary cells have the properties of embryonic stem cells (ESC), including the expression of appropriate immunological markers and the capability of forming embryoid bodies. The subcultured cells also show the characteristics of stem cells, such as the expression of CK19, beta(1-)integrin, P63, and formation of holo-clones in culture. Therefore, we termed these cells epidermal adult stem cells (EpiASC), although their origin was not identified. We have shown that clones of individual EpiASC proliferate and differentiate in culture to produce neurons, cardiomyocytes, osteoblasts, and occytes. Further, we cultivated EpiASC on bioengineered dermis and denuded human amniotic membrane (HAM), to reconstruct artificial skin and corneal epithelium. We successfully transplanted those artificial tissues in goats with acute full-thickness skin defect (AFTSD) and limbal stem cell deficiency (LSCD), respectively. Our results showed that indeed EpiASC reconstructed the skin (hair was observed in restored areas), and repaired the damaged cornea of goats with total LSCD. These data confirm that EpiASC can differentiate into different functional cell types in vivo or in vitro. Due to their high degree of inherent plasticity, and to their easy accessibility for collection from the skin, EpiASC are excellent candidate sources for diverse cell therapies.     

Juvenile versus adult competition

A general class of age-structured models based upon the McKendrick/von Foerster equations are used to study intraspecific competition between juveniles and adults. Criteria for the existence and stability of equilibria are obtained and the dependence of equilibrium stability (i.e. equilibrium resilience) on competition coefficients is analyzed for low inherent net reproductive numbers. The results are applied to the question of whether juvenile vs. adult intraspecific competition is stabilizing or destabilizing. Two types of competition are studied. The first, involving suppressed adult fertility due to competition from juveniles, was found to be destabilizing in that equilibrium levels are lowered and equilibrium resilience weakened by increased competition. The second, involving increased juvenile mortality due to competition from adults, was found to be considerably more complicated. While equilibrium levels were again reduced by increased competition, equilibrium resilience can either be weakened or strengthened. A criterion for determining the effects on resilience is derived and several examples are given to illustrate various possibilities in this case.The author gratefully acknowledges the support of the Applied Mathematics Division and the Population Biology/Ecology Division of the National Science Foundation under NSF grant No. DMS-8902508Research supported by the Department of Energy under contracts W-7405-ENG-36 and KC-07-01-01     

Embryonic and adult vasculogenesis

Two mechanisms account for the formation of blood vessels, vasculogenesis and angiogenesis. Unfortunately, the terms vasculogenesis and angiogenesis literally have the same meaning, i.e., the genesis of blood vessels, and thus do little to distinguish between the two processes. Despite the nomenclature, the two processes are clearly distinct. Vasculogenesis, the de novo formation of blood vessels from mesoderm, is driven by the recruitment of undifferentiated mesodermal cells to the endothelial lineage and the de novo assembly of such cells into blood vessels. Angiogenesis is the generation of new blood vessels from endothelial cells of existing blood vessels, a process driven by endothelial cell proliferation. Recent years have seen dramatic changes in our understanding of the process of vasculogenesis, expanding the scope of its occurrence beyond the earliest stages of development to include involvement in neovascular processes throughout development as well as in the adult. In this review, emphasis is placed on discussion of emerging perspectives on the process of vasculogenesis in both the embryo and the adult.     

Micropropagation of adult avocado

A procedure has been developed to successfully micropropagate the IV-8 selection, an adult avocado rootstock. Cultures were initiated from basal shoots obtained after pruning a tree back to ground level. Buds sprouted in Murashige and Skoog solid medium with macroelements at half strength and a 1.3 μM benzyladenine supplement. To induce proliferation, shoots were cultured for 2 weeks in liquid medium in a rollordrum with the Gamborg salt formulation and 1.3 μM benzyladenine, followed by 6 weeks in double phase conditions (solid medium with a layer of liquid medium on the top) using the same salt formulation and two different benzyladenine supplements, 2.8 μM in the solid phase and 0.4 μM in the liquid phase. Ninety percent of the shoots rooted after a 3-day culture in liquid medium in a rollordrum with MS macroelements at 0.3× and 4.9 μM indolebutyric acid, followed by transfer to solid medium in the absence of auxin but with 1 g l⁻¹ activated charcoal. Survival rate during the acclimatization in the greenhouse was 70%. This revised version was published online in June 2006 with corrections to the Cover Date.     

Larval and adult brains

Apical organs are a well-known structure in almost all ciliated eumetazoan larvae, although their function is poorly known. A review of the literature indicates that this small ganglion is the "brain" of the early larva, and it seems probable that it represents the brain of the ancestral, holopelagic ancestor of all eumetazoans, the gastraea. This early brain is lost before or at metamorphosis in all groups. Protostomes (excluding phoronids and brachiopods) appear to have brains of dual origin. Their larvae develop a pair of cephalic ganglia at the episphere lateral to the apical organ, and these two ganglia become an important part of the adult brain. The episphere and the cerebral ganglia show Otx expression, whereas Hox gene expression has not been seen in this part of the brain. A ventral nervous system develops around the blastopore, which becomes divided into mouth and anus by fusion of the lateral blastopore lips. The circumblastoporal nerve ring becomes differentiated into a nerve ring around the mouth, becoming part of the adult brain, a pair of ventral nerve cords, in some cases differentiated into a chain of ganglia, and a ring around the anus. This part of the nervous system appears to be homologous with the oral nerve ring of cnidarians. This interpretation is supported by the expression of Hox genes around the cnidarian mouth and in the ventral nervous system of the protostomes. The development of phoronids, brachiopods, echinoderms, and enteropneusts does not lead to the formation of an episphere or to differentiation of cerebral ganglia. In general, a well-defined brain is lacking, and Hox genes are generally not expressed in the larval organs, although this has not been well studied.     

Dopamine and adult neurogenesis

Dopamine is an important neurotransmitter implicated in the regulation of mood, motivation and movement. We have reviewed here recent data suggesting that dopamine, in addition to being a neurotransmitter, also plays a role in the regulation of endogenous neurogenesis in the adult mammalian brain. In addition, we approach a highly controversial question: can the adult human brain use neurogenesis to replace the dopaminergic neurones in the substantia nigra that are lost in Parkinson's disease?     

Tracking adult stem cells

The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context, rather than outside their natural environment. The mouse is an attractive model in which to study adult mammalian stem cells, as numerous experimental systems and genetic tools are available. In this review, we describe strategies commonly used to identify and functionally characterize adult stem cells in mice and discuss their potential, limitations and interpretations, as well as how they have informed our understanding of adult stem-cell biology. An accurate interpretation of physiologically relevant stem-cell assays is crucial to identify adult stem cells and elucidate how they self-renew and give rise to differentiated progeny.     

A primary culture technique of adult retina for regeneration studies on adult CNS neurons

This protocol details a tissue culture technique that allows for quantified regeneration studies on adult retinal ganglion cells (RGCs), that is, CNS neurons. The method may also allow for elucidation of molecular cues, for example of signals relevant in neuronal survival and axon regeneration. The procedure relies on fractioned stripe culture of previously injured retina in defined culture media. Naive dendritic cell contacts of RGCs are preserved, and the system is independent of growth factors. In contrast to other techniques, the protocol is based on tissue grown from adult animals; it dispenses immature co-cultures and evaluates the outgrowth of unmyelinated neurites in a milieu lacking CNS myelin. The technique is suitable for rodent retina from mouse or rat. A growth-conditioning injury of the optic nerve is set 10 days before retinal explantation. Explants are cultured for 5-7 days. Mere preparation of a single retina should be completed within 20 min.     

Differentiation of adult Leydig cells

Adult Leydig cells originate within the testis postnatally. Their formation is a continuous process involving gradual transformation of progenitors into the mature cell type. Despite the gradual nature of these changes, studies of proliferation, differentiation and steroidogenic function in the rat Leydig cell led to the recognition of three distinct developmental stages in the adult Leydig cell lineage: Leydig cell progenitors, immature Leydig cells and adult Leydig cells. In the first stage, Leydig cell progenitors arise from active proliferation of mesenchymal-like stem cells in the testicular interstitium during the third week of postnatal life and are recognizable by the presence of Leydig cell markers such as histochemical staining for 3β-hydroxysteroid dehydrogenase (3β-HSD) and the present of luteinizing hormone (LH) receptors. They proliferate actively and by day 28 postpartum differentiate into immature Leydig cells. In the second stage, immature Leydig cells are morphologically recognizable as Leydig cells. They have an abundant smooth endoplasmic reticulum and are steroidogenically active, but primarily produce 5-reduced androgens rather than testosterone. Immature Leydig cells divide only once, giving rise to the total adult Leydig cell population. In the third and final stage, adult Leydig cells are fully differentiated, primarily produce testosterone and rarely divide. LH and androgen act together to stimulate differentiation of Leydig cell progenitors into immature Leydig cells. Preliminary data indicate that insulin like growth factor-1 (IGF-1) acts subsequently in the transformation of immature Leydig cells into adult Leydig cells.     

Health of adult free-living cheetahs

Health of free-living adult cheetahs was assessed using haematological and biochemical measurements of condition. Results showed that cheetahs of both sexes varied on several of these measures, demonstrating that their genetic monomorphism does not result in individuals being of equivalent health. Differences in condition appeared to be somewhat associated with sex, age and whether males were territorial. Compared to two different groups of captive cheetahs, free-living cheetahs were monocytotic, and free-living females were macrocytic. Limited data from captive animals showed they ate more than their free-living counterparts, possibly reflecting the elevated blood glucose levels of captive cheetahs.     

Aspiration cytology of adult rhabdomyoma

The distinct cytologic picture of a fine needle aspirate from a case of adult rhabdomyoma is described. The presence of cytoplasmic cross striations was a diagnostic feature that could be demonstrated in some tumor cells with all routine stains used (Papanicolaou, May-Grünwald-Giemsa and hematoxylin and eosin).     

Reported versus measured adult statures

Reported and measured statures were obtained for 100 husband-wife pairs. In addition, wives were asked to specify whether their husbands were tall, medium, or short. Correlations between reported and measured statures are high (0.84–0.97) and wives tend to overestimate their own measured stature by about 1 cm, and that of their husbands by about 1.3 cm. Wives correctly classify their husbands as tall, medium, or short in about 70% of the cases, using terciles of the stature distribution of American men as the standard. Reported statures may be useful proxies for measured statures for certain purposes. In the absence of measured or reported statures, a wife's categorization of her husband as tall, medium, or short may be satisfactory for some group studies.     

Prematurity and adult minor illness

The long term impact of being born premature has received limited scientific investigation. Studies that have been carried out, focus on outcomes in childhood, with very few considering the impact on adult physical health. Three case studies are presented here, investigating differences in adult minor illness and psychological variables between adult participants born preterm, fullterm but small and fullterm with normal birthweight. This is a retrospective design using questionnaires and checklist to gather relevant information. Minor illness symptoms, daily hassles, anxiety, depression and general self-efficacy were measured. The participant born preterm scored higher on all measures. Data were applied to the Equilibrium Model for Minor Illness. Being born early appears to have a greater impact on later adult outcomes measured than being born fullterm but small or fullterm but of normal weight. In this article the authors reflect upon possible explanations for the different outcomes of each of the participants within the foetal origins of disease theory.     

Culture of adult mouse neurons

Primary neuronal cells used to model physiology are generally limited to embryonic tissue. However, embryonic tissue is not optimal as a model for age-related changes in physiology or late-onset disease. Successful culturing of neurons from adult animals, however, has been historically difficult, if not impossible. Here, we report methodology for routine and reliable cultivation of healthy striatal neurons from adult mice. The new methodology is cost-effective and improves the speed and simplicity of neuronal isolation.